U.S. Pat. No. 4,071,478 describes the use of crosslinked polymers containing quaternary ammonium groups in the polymer backbone which are separated by trimethylene groups. No mention is made of the use of polymers containing ammonium salts which are not quaternary ammonium salts.
U.S. Pat. No. 4,775,384 describes the reaction of various organic compounds containing two halogen groups with various diamines to form polymeric ammonium salts. These salts are described as water soluble, and are thus not crosslinked. After further reactions, they are described as being useful as fiber finishes.
U.S. Pat. No. 4,147,586 describes the reaction of certain dihaloalkanes with alkylene diamines to form "adducts" which are water soluble. The adducts are useful, after reaction with an epihalohydrin, for increasing the wet strength of paper.
Several different types of bile acid sequestrants are known. Some of these are polymers which contain ammonium salts (amine groups in the salt form) which are bound to or are part of a polymer molecule. Such polymers vary in their ability to bind bile acids, their toxicity and their ease of administration. Thus, improved bile acid sequestrants are still being sought.
U.S. Pat. No. 3,383,281 describes the use of crosslinked polymers containing amine groups as bile acid sequestrants. In particular, the use of crosslinked styrenes containing quaternary ammonium groups is described. Such resins, which are also useful as ion exchange resins, are believed to be the active ingredient in the commercially available cholestyramine which is used to lower blood cholesterol levels.
U.S. Pat. No. 4,027,009 describes the use of linear (not crosslinked) polymers containing quaternary ammonium groups in the polymer backbone as bile acid sequestrants. The nitrogen atoms of the polymer are connected by methylene chains of designated size, or other designated groups. No mention is made in this patent of the use of crosslinked polymers (except as background information), or the use of polymers containing ammonium salts that are not quaternary ammonium salts.
U.S. Pat. No. 5,236,701 describes a crosslinked polymeric material useful as a bile acid sequestrant which has amine group on polymer branches which are end groups. The amine groups are not part of the crosslinked network.
R. De Simone, et al., Journal of Pharmaceutical Sciences, vol. 67, p. 1695-1698 (1978) describes the preparation and use of an analog of "Cholestyramine" which is "microporous".